To sleep, perchance to recharge

We humans spend approximately one-third of our lives embroiled in a scientific mystery, which is to say, asleep. After a hectic day at the veterinary clinic (or possibly during a tedious sales call) we crave sleep and can barely stave it off. But what exactly is the purpose of sleeping? Though there are wide ranging theories, there has never been agreement as to the precise biological function of this daily act.

Now, a study conducted at the Center for Sleep Research at the Semel Institute for Neuroscience and Human Behavior at UCLA has made new assertions about the role of sleep. UCLA professor of psychiatry Jerome Siegel's lab analyzed the sleep habits of a wide variety of animals and concluded, in research presented in the online version of the journal Nature Reviews Neuroscience, that sleep's primary utilities are those of increasing efficiency and reducing risk.

In terms of efficiency, though the human brain accounts for only 2 percent of body weight on average, it consumes 20 percent of our energy to function during times of waking. Sleeping provides periods of energy conservation leading to an overall more efficient use of resources. As for risk reduction, Siegel maintains that sleeping affects our overall patterns of behavior, essentially dictating that we are out of harm's way and consuming less energy at regular periods.

These evaluations are contrary to past opinions which held that dozing had negative value for survival by leaving sleepers incapacitated and unable to perform essential tasks as well as at risk to predation.

So, the next time you're tardy to an appointment from oversleeping try this excuse: "Sorry I'm late-I was performing biological regulation."